Attentional demand influences strategies for encoding into visual working memory

Visual selective attention and visual working memory (WM) share the same capacity-limited resources. We investigated whether and how participants can cope with a task in which these 2 mechanisms interfere. The task required participants to scan an array of 9 objects in order to select the target locations and to encode the items presented at these locations into WM (1 to 5 shapes). Determination of the target locations required either few attentional resources (“popout condition”) or an attention-demanding serial search (“non pop-out condition”). Participants were able to achieve high memory performance in all stimulation conditions but, in the non popout conditions, this came at the cost of additional processing time. Both empirical evidence and subjective reports suggest that participants invested the additional time in memorizing the locations of all target objects prior to the encoding of their shapes into WM. Thus, they seemed to be unable to interleave the steps of search with those of encoding. We propose that the memory for target locations substitutes for perceptual pop-out and thus may be the key component that allows for flexible coping with the common processing limitations of visual WM and attention. The findings have implications for understanding how we cope with real-life situations in which the demands on visual attention and WM occur simultaneously. Keywords: attention, working memory, interference, encoding strategie

Interaktionen zwischen visuellem Arbeitsgedächtnis und Aufmerksamkeit

Visual working memory (WM) and selective attention are fundamental cognitive mechanisms, both operating at the interface between perception and action. They are related because both are postulated to have limits with respect to how much information can be processed. Specifically, selective attention has been implicated as a limiting factor for the storage capacity of visual WM. However, visual WM and attention have been largely studied in isolation and interactions between the two have rarely been addressed. This dissertation aimed at investigating interactions between selective attention and the encoding of information into visual WM in the context of one common characteristic feature, namely their limitation in capacity. An experimental task was used that combined visual search with delayed discrimination and the demands on selective attention and WM encoding were manipulated orthogonally. In each trial participants were presented with a search array consisting of nine different grey geometric shapes. A small L-shaped item that appeared in one of four different orientations and that was coloured either blue or red was placed in the centre of each shape. Participants were instructed to search for predefined target items (Ls oriented 90°) and to memorise the shapes associated with these target items. After a delay phase a probe was presented and participants decided whether it did or did not match one of the memorised shapes. Attentional demand was manipulated by changing the search efficiency in the visual search component of the task (easy vs. difficult search) and WM load was manipulated by the number of targets (1 to 5). A behavioural study was conducted to isolate the processes that allowed participants to successfully encode complex shapes into WM while engaging spatial attention for a visual search task. The data provided evidence for a two-step encoding strategy. In the first step participants selected and memorised only the locations of all target items and only then they encoded the associated shapes at a later step. This strategy allowed them to cope with the interference between WM and attention that would otherwise take place. In the second part of this dissertation interference between visual attention and the encoding into visual WM was investigated on the level of neural activation using functional magnetic resonance imaging (fMRI). Specifically, the hypothesis was tested that the capacity limitation of visual WM is due to common limited-capacity neural resources shared by visual WM and attention. Two separate fMRI experiments were conducted that combined visual search and delayed visual discrimination for either objects (experiment 1) or locations (experiment 2). The results revealed overlapping activation for attention-demanding visual search and object WM encoding in distributed posterior and frontal regions. In the right prefrontal cortex and bilateral insula BOLD activation additively increased with increased WM load and attentional demand. Conversely, the analysis revealed an interaction effect in several visual, parietal, and premotor areas. These regions showed overlapping activation for the two task components and were severely reduced in their WM load response under the condition with high attentional demand. This interaction effect was found in similar frontal and posterior regions when combining visual search and spatial WM encoding in experiment 2. In contrast, regions in the prefrontal cortex were selectively responsive to WM load and differed to some degree depending on the WM domain. Here, activation associated with increased WM load was delayed rather than reduced under high attentional demand. The fMRI results provide convergent evidence that visual selective attention and the encoding of information into WM share, to a high degree, common neural resources. The findings indicate that competition for resources shared by visual attention and WM encoding can limit processing capabilities in distributed posterior brain regions but not the prefrontal cortex. The findings support the view that WM evolves from the recruitement of attentional mechanisms (Cowan, 2001; Wheeler und Treisman, 2002) the very same that act upon perceptual representations as well (Slotnick, 2004; Jonides et al., 2005; Pasternak and Greenlee, 2005; Postle, 2006; Ranganath, 2006). The similarity in the effects of interference between attention and the encoding of objects or locations into WM indicates that the attention-based model of WM encoding is valid across different WM domains. The capacity of visual WM can be limited at various stages of processing. The behavioural and fMRI data presented in this dissertation illustrate that one major bottleneck of information processing arises from the common demands on neural and cognitive resources shared between visual WM and selective attention during the encoding stage.Selektive visuelle Aufmerksamkeit und das visuelle Arbeitsgedächtnis (AG) stellen fundamentale kognitive Mechanismen an der Schnittstelle zwischen Wahrnehmen und Handeln dar. Ein gemeinsamer zentraler Aspekt ist ihre begrenzte Kapazität. Aufmerksamkeitsprozesse werden als ein limitierender Faktor der Kapazität des visuellen AGs diskutiert. AG- und Aufmerksamkeitsprozesse wurden jedoch bisher überwiegend in separaten Experimenten untersucht und die Beziehung zwischen diesen kognitiven Systemen ist unzureichend geklärt. Das Ziel der vorliegenden Arbeit war es, Interaktionen zwischen den Prozessen der selektiven Aufmerksamkeit und der Enkodierung in das visuelle AG im Kontext ihrer begrenzten Verarbeitungskapazität zu untersuchen. Es wurde eine Aufgabe entwickelt, in der die Anforderungen an beide Mechanismen unabhängig von einander manipuliert wurden. Den Probanden wurde ein visuelles Feld bestehend aus neun Figuren präsentiert. Jede Figur war in der Mitte mit einem farbigen, L-förmigen Winkel markiert. Die Probanden waren instruiert, nach zuvor definierten Zielwinkeln zu suchen und sich die so markierten Figuren zu merken. Nach einer Haltephase wurde den Probanden ein Testreiz dargeboten, der mit den zuvor gespeicherten Figuren abzugleichen war. Die Gedächtnislast wurde über die Anzahl der zu enkodierenden Figuren manipuliert (1 bis 5). Die Aufmerksamkeitsanforderung wurde über den Schwierigkeitsgrad der visuellen Suche bestimmt (einfach vs. schwierig). In einer Verhaltensstudie konnten die kognitiven Prozesse isoliert werden, die es den Probanden ermöglichten, komplexe Figuren trotz interferierender Aufmerksamkeitsanforderungen erfolgreich in das AG zu enkodieren. Die Ergebnisse wiesen auf eine zweistufige Enkodierungsstrategie hin, die das Detektieren und Memorieren der Positionen aller Zielwinkel vor der Enkodierung der relevanten Figuren umfasste. Die anschließende Untersuchung mittels funktioneller Magnetresonanztomographie (fMRT) diente dazu, Interaktionen zwischen diesen Prozessen auf neuronaler Ebene zu charakterisieren. Es wurde die Hypothese getestet, dass die Kapazitätslimitierung des visuellen AGs auf begrenzte neuronale Ressourcen zurückzuführen sei, die gemeinsam von AG- und Aufmerksamkeitsprozessen beansprucht werden. Dazu wurden zwei fMRT-Experimente durchgeführt, in denen die visuelle Suche mit der Enkodierung von Figuren (Experiment 1) bzw. Positionen (Experiment 2) kombiniert wurde. Die Ergebnisse zeigten für die schwierige visuelle Suche und die Enkodierung von Figuren stark überlappende Aktivierungsmuster in verteilten posterioren und frontalen Arealen. Im rechten präfrontalen Kortex und beidseitig in der Inselregion stieg das fMRT-Signal additiv mit zunehmender AG-Last und zunehmender Aufmerksamkeitsanforderung an. Im Gegensatz dazu war in mehreren visuellen, parietalen und prämotorischen Arealen der Effekt der AG-Manipulation in Kombination mit der schwierigen visuellen Suche geringer ausgeprägt als in Kombination mit der einfachen visuellen Suche. Dieser Interaktionseffekt konnte für die Kombination der visuellen Suche mit der Enkodierung von Positionen (Experiment 2) in ähnlichen posterioren Arealen lokalisiert werden. Regionen im Präfrontalkortex waren mit einem Aktivitätsanstieg assoziiert, der selektiv mit der zunehmenden AG-Last korreliert war und in der schwierigen Suchbedingung zeitlich verzögert auftrat. Im Präfrontalkortex konnten zudem materialspezifische Aktivitätsmuster aufgezeigt werden. Die Ergebnisse der fMRT-Experimente zeigten übereinstimmend, dass die Enkodierung von Information in das visuelle AG und visuelle selektive Aufmerksamkeit größtenteils auf gemeinsamen neuronalen Ressourcen beruhen. Der Wettbewerb um begrenzte Ressourcen, die von Enkodierungs- und Aufmerksamkeitsprozessen beansprucht werden, scheint die Verarbeitungskapazität in verteilten posterioren Arealen zu limitieren. Die Befunde stehen im Einklang mit kognitiven Modellen, die Aufmerksamkeitsprozessen eine funktionale Bedeutung für das kurzfristige Halten von Informationen zuschreiben (Cowan, 2001; Wheeler und Treisman, 2002) und unterstützen die Annahme, dass dem AG die gleichen kognitiven und neuronalen Ressourcen zugrunde liegen, die auch für die perzeptuelle Verarbeitung herangezogen werden (Slotnick, 2004; Jonides et al., 2005; Postle, 2006). Die vorliegenden Resultate geben darüber hinaus Hinweise auf eine materialunabhängige Gültigkeit dieser Modelle. Kapazitätsbegrenzungen des visuellen AGs können an verschiedenen Stufen der Verarbeitung zum Tragen kommen. Die Befunde der vorgestellten Verhaltens- und fMRT-Experimente verdeutlichen, dass begrenzte neuronale und kognitive Ressourcen, die gemeinsam von den Mechanismen der visuellen Aufmerksamkeit und des visuellen AG beansprucht werden, zu einem Flaschenhals in der Informationsverarbeitung während der Phase der Enkodierung führen können

Ten years Center for Immersive Visualizations - Past, Present, and Future

Virtual Reality (VR) can be found in many fields. A majority of the time this involves the use of Head-Mounted Displays (HMDs). Their alternatives, large-scale immersive 3D screens and CAVE systems, can also be found in research and offer researchers high visual quality and collaborative VR experiences. This report covers the operation and learnings from maintaining a visualization center with large-scale immersive installations over the course of ten years

The dynamical association between physical activity and affect in the daily life of individuals with ADHD

ADHD, Mood; Physical activityTDAH; Estado anímico; Actividad físicaTDAH; Estat anímic; Activitat físicaExercise interventions in mental disorders have evidenced a mood-enhancing effect. However, the association between physical activity and affect in everyday life has not been investigated in adult individuals with ADHD, despite being important features of this disorder. As physical activity and affect are dynamic processes in nature, assessing those in everyday life with e-diaries and wearables, has become the gold standard. Thus, we used an mHealth approach to prospectively assess physical activity and affect processes in individuals with ADHD and controls aged 14–45 years. Participants wore accelerometers across a four-day period and reported their affect via e-diaries twelve times daily. We used multilevel models to identify the within-subject effects of physical activity on positive and negative affect. We split our sample into three groups: 1. individuals with ADHD who were predominantly inattentive (n = 48), 2. individuals with ADHD having a combined presentation (i.e., being inattentive and hyperactive; n = 95), and 3. controls (n = 42). Our analyses revealed a significant cross-level interaction (F(2, 135.072)=5.733, p = 0.004) of physical activity and group on positive affect. In details, all groups showed a positive association between physical activity and positive affect. Individuals with a combined presentation significantly showed the steepest slope of physical activity on positive affect (slope_inattentive=0.005, p<0.001; slope_combined=0.009, p<0.001; slope_controls=0.004, p = 0.008). Our analyses on negative affect revealed a negative association only in the individuals with a combined presentation (slope=-0.003; p = 0.001). Whether this specifically pronounced association in individuals being more hyperactive might be a mechanism reinforcing hyperactivity needs to be empirically clarified in future studies

Attentional demand influences strategies for encoding into visual working memory

Visual selective attention and visual working memory (WM) share the same capacity-limited resources. We investigated whether and how participants can cope with a task in which these 2 mechanisms interfere. The task required participants to scan an array of 9 objects in order to select the target locations and to encode the items presented at these locations into WM (1 to 5 shapes). Determination of the target locations required either few attentional resources (“popout condition”) or an attention-demanding serial search (“non pop-out condition”). Participants were able to achieve high memory performance in all stimulation conditions but, in the non popout conditions, this came at the cost of additional processing time. Both empirical evidence and subjective reports suggest that participants invested the additional time in memorizing the locations of all target objects prior to the encoding of their shapes into WM. Thus, they seemed to be unable to interleave the steps of search with those of encoding. We propose that the memory for target locations substitutes for perceptual pop-out and thus may be the key component that allows for flexible coping with the common processing limitations of visual WM and attention. The findings have implications for understanding how we cope with real-life situations in which the demands on visual attention and WM occur simultaneously

The serotonin receptor 3E variant is a risk factor for female IBS-D

Irritable bowel syndrome (IBS) is a gut-brain disorder of multifactorial origin. Evidence of disturbed serotonergic function in IBS accumulated for the 5-HT3 receptor family. 5-HT3Rs are encoded by HTR3 genes and control GI function, and peristalsis and secretion, in particular. Moreover, 5-HT3R antagonists are beneficial in the treatment of diarrhea predominant IBS (IBS-D). We previously reported on functionally relevant SNPs in HTR3A c.-42C > T (rs1062613), HTR3C p.N163K (rs6766410), and HTR3E c.*76G > A (rs56109847 = rs62625044) being associated with IBS-D, and the HTR3B variant p.Y129S (rs1176744) was also described within the context of IBS. We performed a multi-center study to validate previous results and provide further evidence for the relevance of HTR3 genes in IBS pathogenesis. Therefore, genotype data of 2682 IBS patients and 9650 controls from 14 cohorts (Chile, Germany (2), Greece, Ireland, Spain, Sweden (2), the UK (3), and the USA (3)) were taken into account. Subsequent meta-analysis confirmed HTR3E c.*76G > A (rs56109847 = rs62625044) to be associated with female IBS-D (OR = 1.58; 95% CI (1.18, 2.12)). Complementary expression studies of four GI regions (jejunum, ileum, colon, sigmoid colon) of 66 IBS patients and 42 controls revealed only HTR3E to be robustly expressed. On top, HTR3E transcript levels were significantly reduced in the sigma of IBS patients (p = 0.0187); more specifically, in those diagnosed with IBS-D (p = 0.0145). In conclusion, meta-analysis confirmed rs56109847 = rs62625044 as a risk factor for female IBS-D. Expression analysis revealed reduced HTR3E levels in the sigmoid colon of IBS-D patients, which underlines the relevance of HTR3E in the pathogenesis of IBS-D

Understanding the effects of Covid-19 through a life course lens

The Covid-19 pandemic is shaking fundamental assumptions about the human life course in societies around the world. In this essay, we draw on our collective expertise to illustrate how a life course perspective can make critical contributions to understanding the pandemic’s effects on individuals, families, and populations. We explore the pandemic’s implications for the organization and experience of life transitions and trajectories within and across central domains: health, personal control and planning, social relationships and family, education, work and careers, and migration and mobility. We consider both the life course implications of being infected by the Covid-19 virus or attached to someone who has; and being affected by the pandemic’s social, economic, cultural, and psychological consequences. It is our goal to offer some programmatic observations on which life course research and policies can build as the pandemic’s short- and long-term consequences unfold

Bright light therapy versus physical exercise to prevent co-morbid depression and obesity in adolescents and young adults with attention-deficit/hyperactivity disorder: study protocol for a randomized controlled trial

Background: The risk for major depression and obesity is increased in adolescents and adults with attention-deficit / hyperactivity disorder (ADHD) and adolescent ADHD predicts adult depression and obesity. Non-pharmacological interventions to treat and prevent these co-morbidities are urgently needed. Bright light therapy (BLT) improves day– night rhythm and is an emerging therapy for major depression. Exercise intervention (EI) reduces obesity and improves depressive symptoms. To date, no randomized controlled trial (RCT) has been performed to establish feasibility and efficacy of these interventions targeting the prevention of co-morbid depression and obesity in ADHD. We hypothesize that the two manualized interventions in combination with mobile health-based monitoring and reinforcement will result in less depressive symptoms and obesity compared to treatment as usual in adolescents and young adults with ADHD. Methods: This trial is a prospective, pilot phase-IIa, parallel-group RCT with three arms (two add-on treatment groups [BLT, EI] and one treatment as usual [TAU] control group). The primary outcome variable is change in the Inventory of Depressive Symptomatology total score (observer-blinded assessment) between baseline and ten weeks of intervention. This variable is analyzed with a mixed model for repeated measures approach investigating the treatment effect with respect to all three groups. A total of 330 participants with ADHD, aged 14 – < 30 years, will be screened at the four study centers. To establish effect sizes, the sample size was planned at the liberal significance level of α = 0.10 (two-sided) and the power of 1-β = 80% in order to find medium effects. Secondary outcomes measures including change in obesity, ADHD symptoms, general psychopathology, health-related quality of life, neurocognitive function, chronotype, and physical fitness are explored after the end of the intervention and at the 12-week follow-up. This is the first pilot RCT on the use of BLT and EI in combination with mobile health-based monitoring and reinforcement targeting the prevention of co-morbid depression and obesity in adolescents and young adults with ADHD. If at least medium effects can be established with regard to the prevention of depressive symptoms and obesity, a larger scale confirmatory phase-III trial may be warranted.The trial is funded by the EU Framework Programme for Research and Innovation, Horizon 2020 (Project no. 667302). Funding period: January 2016–December 2020. This funding source had no role in the design of this study and will not have any role during its execution, analyses, interpretation of the data, or decision to submit results. Some local funds additionally contributed to carry out this study, especially for the preparation of the interventions: FBO research activity is by the Spanish Ministry of Economy and Competitiveness – MINECO (RYC-2011-09011) and by the University of Granada, Plan Propio de Investigación 2016, Excellence actions: Unit of Excellence on Exercise and Health (UCEES)

The serotonin receptor 3E variant is a risk factor for female IBS-D

Irritable bowel syndrome (IBS) is a gut-brain disorder of multifactorial origin. Evidence of disturbed serotonergic function in IBS accumulated for the 5-HT receptor family. 5-HT Rs are encoded by HTR3 genes and control GI function, and peristalsis and secretion, in particular. Moreover, 5-HT R antagonists are beneficial in the treatment of diarrhea predominant IBS (IBS-D). We previously reported on functionally relevant SNPs in HTR3A c.-42C > T (rs1062613), HTR3C p.N163K (rs6766410), and HTR3E c.*76G > A (rs56109847 = rs62625044) being associated with IBS-D, and the HTR3B variant p.Y129S (rs1176744) was also described within the context of IBS. We performed a multi-center study to validate previous results and provide further evidence for the relevance of HTR3 genes in IBS pathogenesis. Therefore, genotype data of 2682 IBS patients and 9650 controls from 14 cohorts (Chile, Germany (2), Greece, Ireland, Spain, Sweden (2), the UK (3), and the USA (3)) were taken into account. Subsequent meta-analysis confirmed HTR3E c.*76G > A (rs56109847 = rs62625044) to be associated with female IBS-D (OR = 1.58; 95% CI (1.18, 2.12)). Complementary expression studies of four GI regions (jejunum, ileum, colon, sigmoid colon) of 66 IBS patients and 42 controls revealed only HTR3E to be robustly expressed. On top, HTR3E transcript levels were significantly reduced in the sigma of IBS patients (p = 0.0187); more specifically, in those diagnosed with IBS-D (p = 0.0145). In conclusion, meta-analysis confirmed rs56109847 = rs62625044 as a risk factor for female IBS-D. Expression analysis revealed reduced HTR3E levels in the sigmoid colon of IBS-D patients, which underlines the relevance of HTR3E in the pathogenesis of IBS-D. [Abstract copyright: © 2022. The Author(s).